Last time, we saw how to change existing items in a list using their index, like colors[1] = "yellow".

But what if you want to add a new item to the list without replacing an existing one?

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How might you add to the collection?

Python lists have a special built-in function (called a method) just for this: .append().

This method adds the specified item to the very end of the list. The list grows by one item.

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With me so far?

Here's how you use it: list_name.append(new_item).

If we have tasks = ["review code"], and we run tasks.append("write tests"), the list changes.

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How long do you think the list will be after this operation?

After running the operation the tasks list becomes ["review code", "write tests"]. The new item "write tests" is added at the end.

You can append items of any data type (strings, numbers, Booleans) to a list.

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Do you think you can append a list to a list?